I suspect that using SAPup or SAPEHPI it would likely have been entirely possible to apply EhP1 for NW7.0 without also applying EhP4 for ERP6.0, but as Yves said I don't think this was ever an intended scenario, which is probably why the new tool, SUM, may not support it. I guess the real question is whether you could produce a consistent stack XML in Maintenance Optimizer that applies a NetWeaver EhP without applying the related ERP EhP.
Certainly you wouldn't be able to upgrade NetWeaver to EhP1 using SAINT.
Although you might be able to force the client copy to work in the way using Yves mentions, that won't in itself update the NetWeaver components, as they are of course client-independent. Do you have to do a client copy? What about a system copy? That would take care of it.
Regards,
Matt